• 한국세라믹학회지
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• 제44권12호
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• pp.715-719
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• 2007

STS444 with or without $La_{0.9}Sr_{0.1}MnO_3$ (LSM)-coating was contacted to $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ (LSCF) cathode on various electrolyte materials and the polarization resistance $(R_p)$ was measured by impedance spectroscopy. By making a symmetric half-cell and contacting only one side of the cathode with the interconnect, the effect of chromium (Cr) poisoning was separated from the aging effects. When the LSCF cathode was contacted with LSM-coated STS (stainless steel), $R_p$ of LSCF was lower than that contacted with the uncoated STS. Impedance patterns measured for the working electrode (W.E.), the counter electrode (C.E.) at $600^{\circ}C$ in air were analyzed. Normalized data of net Cr effect showed that $Ce_{0.9}Gd_{0.1}O_2$ (GDC) electrolyte is more tolerant to the chromium poisoning than $La_{0.9}Sr_{0.1}Ga_{0.8}Mg_{0.2}$ (LSGM) or 8 mol% $Y_2O_3-doped$ $ZrO_2$ (YSZ) electrolytes.

• 한국세라믹학회지
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• 제45권12호
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• pp.777-781
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• 2008

Experiments were conducted using SUS430 and Crofer 22 APU steels coated by LSM using plasma spray and slurry spray methods, respectively. High-temperature conductivity and oxidation resistance were investigated. For comparison, SUS430 and Crofer 22 APU without LSM coating were also investigated and coefficient of thermal expansion (CTE) was measured. The results show that the materials without LSM coating exhibit almost the same CTE as YSZ electrolyte in a range of temperatures of $550{\sim}850^{\circ}C$. When coated with LSM, the oxidation rate of the steels decreases by $30{\sim}40%$ using slurry spray and by $10{\sim}30%$ using plasma spray whereas the steels using plasma spray have a better high-temperature conductivity than the steels using slurry spray. It is thus concluded that the LSM coating has a limited effect on increasing high-temperature conductivity while it can effectively reduce the oxidation of the steels.

• 한국세라믹학회지
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• 제42권12호
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• pp.833-841
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• 2005

The oxidation resistance and electrical conductivity of various commercial ferritic stainless steels including STS444 were tested in an air atmosphere at $700^{\circ}C$. Crofer22 developed specially for SOFC interconnect was also examined for the aim of comparing with the test results of STS444. Although STS444 exhibited higher oxidation resistance than Corfer22, the electrical conductivity of the scale formed on Crofer22 was higher, indicating that the resistivity of scale formed on Crofer22 is much lower than that of STS444. To gain a better understanding of the relation between oxidation behavior and electrical conductivity, the oxide scales formed on STS444 and Crofer22 were analyzed in terms of the structure, composition, and phase. Consequently, the influence of alloying elements on electrical conductivity of Fe-Cr alloys was discussed.

• KEPCO Journal on Electric Power and Energy
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• 제5권2호
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• pp.121-125
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• 2019

A YSZ electrolyte based ceramic supported Solid Oxide Cell (SOC) and a metal interconnect supported SOC was investigated under both fuel cell and co-electrolysis (steam and $CO_2$) mode at $800^{\circ}C$. The single cell performance was analyzed by impedance spectra and product gas composition with gas chromatography(GC). The long-term performance in the co-electrolysis mode under a current density of $800mA/cm^2$ was obtained using steam and carbon dioxide ($CO_2$) mixed gas condition.

• 한국세라믹학회지
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• 제48권3호
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• pp.246-250
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• 2011

Effects on sintering and electrical properties of $La_{0.7}Ca_{0.3}Cr_{0.9}Co_{0.1}O_{3-{\delta}}$ system, a interconnect material for cylindrical and flat tubular solid oxide fuel cells (SOFC), have been investigated by Ca-source when using $CaCO_3$ and $CaF_2$. When using $CaCO_3$ and $CaF_2$ was mixing as Ca-source, single phased perovskite solid solution was observed for each sample. The sintering temperature was decreased by $CaF_2$ contents was increased. When using 0.1 mole $CaF_2$ was densely sintered at $1400^{\circ}C$ and relative density was 93.8%. Also, electrical conductivity in oxidation and reducing atmosphere was 47, 4.3 S/cm, respectively, due to $F^-$ ion enhance the electrical conductivity in reducing atmosphere.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.207-207
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• 2008

Modern industry has focused on processing that produce low- loss dielectric substrates used complex micron-sized devices using tick film technologies such as tape casting and slip casting. However, these processes have inherent disadvantages fabricating high density interconnect with embedded passives for high speed communication electronic devices. Here, we have successfully fabricated porous alumina dielectric layer infiltrated with polymer solution by using inkjet printing process. Alumina suspensions were formulated as dielectric ink that were optimized to use in inkjet process. The layer was confirmed by field emission scanning electron microscope (FE-SEM) for measuring microstructure and volume fraction. In addition, the reaction kinetics and electrical properties were characterized by FT-IR and the impedance analyzer. The volume fraction of alumina in porous dielectric alumina layer is around 70% much higher than that in the conventional process. Furthermore, after infiltration on the dielectric layer using polymer resins such as cyanate ester. Excellent Q factors of the dielectric is about 200 when confirmed by impedance analyzer without any high temperature process.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.562-566
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• 2012

본 논문에서는 세그먼트 관형 고체산화물 연료전지(SOFC)의 설계 및 제작과 특성 분석을 다루고 있다. 관형 세라믹 지지체는 압출 공정을 통하여 제작하였으며, NiO-YSZ 연료극과 YSZ 전해질은 담금 코팅법을 통해 세라믹 지지체에 코팅하였다. 코팅된 세라믹 지지체를 $1,350^{\circ}C$에서 5시간 동안 열처리하였으며, $10{\mu}m$ 미만의 치밀하고, 균열이 없는 YSZ 전해질 층을 얻을 수 있었다. 또한 열처리된 세라믹 지지체에 LSM-YSZ/LSM/LSCF로 구성된 다층 구조 공기극을 담금법으로 코팅하여 $1,150^{\circ}C$에서 열처리하였다. 세라믹 관형 지지체에 코팅된 세그먼트 SOFC 셀은 Ag-glass 연결재를 사용하여 전기적으로 직렬 연결하였으며, 수소연료 유량과 운전 온도에 따른 세그먼트 SOFC의 성능 변화를 측정하였다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2005년도 ISMP
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 수소연료전지공동심포지움 2004논문집
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• pp.297-302
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• 2004

• Journal of Electrochemical Science and Technology
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• 제2권1호
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• pp.39-44
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• 2011

Sub-micrometer $La_{0.8}Ca_{0.2}CrO_3$ powders for ceramic interconnects of solid oxide fuel cells were synthesized by the aqueous combustion process. The materials were prepared from the precursor solutions with different glycine (fuel)-to-nitrate (oxidant) ratios (${\phi}$). Single-phase $La_{0.8}Ca_{0.2}CrO_3$ powders with a perovskite structure were obtained after combustion when ${\phi}$ was equal to or larger than 0.480. Especially, the stoichiometric precursor with ${\phi}$ = 0.555 yielded the spherical $La_{0.8}Ca_{0.2}CrO_3$ particles with 150-250 nm diameters after calcination at $1000^{\circ}C$. When compared with the powders synthesized by the solid-state reaction, the combustion-derived, fine powders exhibited improved sinterability, leading to near-full densification at $1400^{\circ}C$ in oxidizing atmospheres. Moreover, a small quantity of glass additives was used to reduce the sintering temperature, and considerable densification was indeed achieved at temperatures as low as $1100^{\circ}C$.